Patent GB-191501240-A (GB)
Title: Improvements in Gyrostatic Apparatus.
Inventor: GRAY JOHN
IPC: G01C19/38
Filed: 1915-01-26
Abstract: 1240. Gray, J., and Gray, J. G. Jan. 26. Gyroscopic apparatus.-A gyroscope is mounted on frames in such a manner that it possesses two instabilities when it is not rotating, and is so controlled that it is rendered completely stable when it is rotating. Such a gyroscope may be utilized as a compass. Fig. 4 shows diagrammatically a compass in which the casing F' of the gyroscope is mounted on vertical pivots b<1> in a frame F<2>, and is rendered unstable therein by a spring s', which connects a crank c<1> forming an extension of one of the pivots and a pillar p' on the frame. The second instability is provided by mounting the frame F<2> in an outer frame F<3> on horizontal pivots b<2>, which are extended to form cranks c<2>, and by connecting these cranks by springs s<2> to pillars p<2> on the frame F<3>. The frame F<3> is free to rotate on a ball-race r, suspended by gimbals g, and carries the compass card c<3>. A reversible motor m is geared to the frame F<3> and is controlled bv a commutator and roller contacts on the frame F' and crank c<1>, respectively. When the gyroscope is out of the meridian and rotating, the tilting-couple consequent on the rotation of the earth causes precession about the pivots b<1> and displacement of the crank c<1> relatively to the frame F<3>. The precession is accelerated by the spring s<1>, so that the frame F<2> is restored to the vertical position, and, the circuit of the motor being completed, the frame F<3> is turned so as to annul the relative displacement of the crank c<1>. The precession, and consequently the turning movement of the frame F<3>, continues until the gyroscope, with or without previous oscillation, settles in the meridian. The motor not only maintains the potential energy of the springs, but also makes good the frictional losses at the bearings, so that the apparatus is virtually frictionless. In a modification, the casing of the gyroscope is mounted on horizontal pivots in a frame turning on vertical pivots in an outer frame mounted on the ballrace r, an arrangement of springs and cranks similar to that shown causing the two instabilities. Constructions of apparatus, illustrating the principles upon which the compass operates, are described. In each of them the frame F' carrying the gyroscope is mounted on horizontal pivots carried by a fork having a vertical shaft, which is rotatable by a motor replacing the motor m, and similarly controlled. In one construction, the first instability is caused by a spring &c., and the second instability is caused by arranging the horizontal pivots below the centre of gravity of the frame F<2>. In two other constructions, the horizontal pivot axis passes through the centre of gravity, so that the equilibrium of the gyroscope is not disturbed by acceleration or retardation of a moving body on which the apparatus may be mounted, or by centrifugal force when the body moves in a curved path. In one of these constructions, both instabilities are caused by springs, as shown in Fig. 4, and in the other by cords carrying weights which replace the springs.